function dy=zhuiji1(t,y)
Vw=450;
Ve=90;
H=120;
dy=zeros(2,1);
dy(1)=Vw/(1+((H-y(2))/(Ve*t-y(1)+eps))^2)^(1/2);
dy(2)=Vw/(1+((Ve*t-y(1))/(H-y(2)))^2)^(1/2);
